The present invention is directed to the field of viscometers. It finds particular application in viscometers used to sense viscosity remotely.
The viscosity of a fluid is important in many situations. In the installation of oil-well casings, for instance, it is often important to know the viscosity of the concrete used for that purpose. In such situations, it is easy to take a sample of the concrete manually, and the sample is manually placed in a viscometer that indicates the viscosity of the concrete.
There are other situations, however, in which, although the viscosity of a fluid is important, viscosity measurement has in the past been too inconvenient to perform routinely. In large earth-moving equipment, for example, changing lubricating oil involves some expense and inconvenience, so a fixed oil-change schedule in which oil changes are too frequent adds to the cost of operation. However, conservative operation requires that the changes be relatively frequent because small changes in temperature or other operating conditions can greatly reduce the life of the lubricating oil, and an oil-change schedule that ordinarily is more than frequent enough can become far too infrequent if conditions change. Since it is possible by measuring viscosity to determine when the time has arrived to change the oil, it would be desirable to change oil only when a measurement of viscosity indicates that an oil change is necessary.
But such measurements are inconvenient. It is time-consuming to take an oil sample for testing outside of the machine on a frequent basis. While it is theoretically possible to employ a dedicated viscometer permanently installed in the machine and providing a remote viscosity indication, existing viscometers do not meet the requirements of simplicity, reliability, and insensitivity to orientation and vibration required in such an application.
It is accordingly an object of the present invention to enable viscosity to be measured remotely by employing a simple device that is relatively insensitive to orientation changes and vibrations.